Bootchart - 25 seconds until gdmgreeter

[lyallp]

I am trying to improve my boot times.
I can have my login screen appear 25 seconds after bios startup, according to http://www.krizka.net/2007/08/20/howto-bootchart-with-bsd-process-accounting-on-gentoo/

Any suggestions? References? Is there a way to document my boot priorities such that others can compare configs and possibly suggest improvements?
My main mechanism for improvement has been to tweak the 'depends upon' entries in /etc/init.d
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...Lyall

[erik258]

switch to openrc (slight improvement), allow rc scripts to start in parallel (modest improvement), or rewrite all of init system as a custom bash script (ridiculously fast, system can boot in almost the time it takes to start kernel).
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[ak47gen]

Use openrc/baselayout2
Clean up all unneeded init.d
Don't use initrd and reconfigured kernel to the basics
Use a lighter software....slim instead of gdm
If possible for fastest boot time use SSD, they have the quickest response time.

If all done correctly you can do things like this.

http://www.youtube.com/watch?v=ozA2ie10A6w

[lyallp]

Ok, switched to slim.

Nice and simple.

It did not seem to like my default XSESSION setting in my /etc/rc.conf file so I put a file in /etc/env.d/99xessions to set XSESSION there) as the environment is loaded by the time I run chooser.sh

I Liked the fingerprint theme but it didn't play nice on my dual head monitor - minor little hack on my part to make the background image as wide as my 2 screens so it didn't get 'stretched' and a minor tweak to the theme config to put the input fields back where they belong after the image changed size.

Already running parallel startup with no splash screen. Fiddling continues. No SSD, just want to see what I can do with my mirrored XFS SATA hard disks.

Slim starts at about 17 seconds.
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...Lyall

[ak47gen]

What about your kernel, are you using genkernel, gentoo sources, and do you have everything additional removed that you don't need?

[lyallp]

gentoo-sources, slimmed down to the hardware I use.

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...Lyall

[lyallp]

Around 17 seconds when slim starts...
http://remotely-helpful.com/bootchart.png
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...Lyall

[Xytovl]

Are you using devtmpfs ? (a kernel compile-time option)
You can remove hwclock if your kernel is configured to set clock from rtc.

If you want to reduce I/O wait, there is ureadahead that might help https://bugs.gentoo.org/show_bug.cgi?id=303044

ntfs mount seems to take some time, if nothing depends on it, use noauto in fstab and create a script to run it after, in parallel with services depending on localmount.

[lyallp]

I am not using devtmpfs, it's marked experimental and I tend to avoid that.

RTC, which option does the RTC setting in kernel?

NTFS, good point. I will think about that one, that requires a bit more work than simply editing the /etc/init.d/ depends values - get it wrong and I will be in a world of pain

Still, 17 seconds isn't too bad
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...Lyall

[erik258]

[lyallp]

CONFIG_RTC_HCTOSYS does not appear to set the RTC on shutdown, at least from the very brief lookup I have done.

Linux is the primary OS on this machine, windoze is a secondary boot (for gaming ).

I happen to like the RTC being right, even after daylight savings changes.
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...Lyall

[Xytovl]

It is up to you, what I mean is that hwclock wastes half a second during boot and that there is a kernel option that does the same thing at no cost (apparently). You can alter the init script to make it do nothing on boot, but save the time on shutdown.

The most important thing is to be able to read the bootchart : when there is no CPU activity and no disk activity at the same time, this means that we are waiting on some HW setup, network etc. It is a god starting point to investigate what could be done at the same time.

[frostschutz]

It's possible to shave some seconds here and there by optimizing init scripts.

For example Gentoo's LVM init scripts waste 10 seconds on boot and 820 seconds on shutdown for me, although that's a bit of a special case in my system ( https://bugs.gentoo.org/show_bug.cgi?id=319017 )

The reason for the 10 seconds on bootup in my case is that it does an additional pvscan I believe, which is rarely ever necessary but takes time nevertheless as it has to look at every attached device. The more devices you have the more time it takes to complete...

That's just an example - if you notice an init script taking a lot of time at bootup, taking a closer look at the particular script and commenting out the stuff you're 100% sure you don't need, can save you quite some time. Of course if you remove something that you actually need you're in a world of pain...

I'd not go for the single bash script approach - hard to maintain IMO. And even if it boots 2 seconds faster it's not worth it using a system that's as far away from standard as it ever could be. Makes emerging stuff and additional services so much harder.

[erik258]

[frostschutz]

Hmmm, a good init system should have its dependencies cached though, so no calculations should need to be done at boot.

I wonder if the difference for your single bash script approach is really that huge? I mean, the main difference between your single bash script and the full fledged init system will not be the separate scripts or its dependencies, but the fact that in your own bash script, you'll only put the things that are absolutely necessary. How big is the difference if you do the same for init scripts? I mean, most init scripts are slow because they have to work on every system and need to be able to handle every situation, so they do a lot of checks that are not relevant to you. For example the alsa init script has to be able to load the correct alsa modules for your card, even if you personally don't use alsa modules at all, so it does some checks that are a complete waste of time on your system, but makes stuff work for others.

The Gentoo init system is the one thing that lacks the modularity you get for packages with use flags; however making a minimalized init system for a distro, is rather complicated and would break things for so many people, that it's not a feasible solution, not even for Gentoo.

[lyallp]

I think the Gentoo init system is really good, particularly the automatic dependency calculation.

I would/do gladly pay the 2 seconds start up time for this. After all, what's 2 seconds in the whole uptime?
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...Lyall